Ryotaro Ichijoin is a supporting character in the original net animation series Love Through a Prism. He is the father of the protagonist, Lili Ichijoin, and resides with his family in Yokohama, Japan. His professional background is that of a kimono maker, a craft that is central to his family's livelihood and legacy. While his wife, Take Ichijoin, imposes a strict ultimatum on their daughter to become the top student at the Saint Thomas Art Academy in London within six months or else return home to abandon her artistic ambitions and inherit the family business, Ryotaro is characterized by his supportive nature regarding Lili's dreams. He serves as a contrast to his wife’s demanding expectations, representing a quieter, more encouraging parental figure who backs Lili’s pursuit of becoming a painter.